Fusing Different Cellular Automata Models for Surface Flows in SCURRI: Viscosity Extension Step

Multicomponent or Macroscopic CellularAutomata (MCA)were conceived for modelling and simulating complex “macroscopic” phenomena such as surface flows, forest fires, bioremediation of soils, etc. Many MCA models were developed for risky surface flows of different typology (lava flows, debris/mud/granular flows, lahars, snow avalanches, pyroclastic flows, rain runoff), these models share many “elementary” processes, but differ in some specificities of the particular phenomenon to be simulated. These specificities could be generalized to a single model (SCURRI: Simulation byCellularUnits of the Rheological RIsks) valid for each surface flow we deal with. The base of SCURRI is given by SCIDDICA, including its derivativeMCAmodels LLUNPIY, VALANCA for simulating single phase surface flows (debris/mud/granular flows, lahars, snow avalanches). We introduce viscosity effects in SCURRI by adopting the approach of the MCA model SCIARA for simulating lava flows: a critical height, beyond which the flows become negligible, is introduced in SCURRI now version 01. SCURRI-01 was applied to a real event (of course) different from a lava flow: the secondary lahar of February 2005 of Vascún Valley from Tungurahua. This event had been simulated satisfactorily by LLUNPIY. Simulations were also performed by SCURRI-01with different values of critical height.Higher values of this parameter, produce clear viscosity increasing effects such as speed decrease which can reach so low values that we can no longer talk about lahars, but rather of slow flow landslide.